Screen and process of making the same



NOV. 12, 1935. I 2,020,787

SCREEN AND PROCESS OF MAKING THE SAME Filed Jan. 27, 1955 Patented Nov. 12, 1935 SCREEN AND PROCESS OF MAKING THE SAME David E. Knapp, Beacon, N. Y. Application January 2'7, 1933, Serial No. 653,906

, 2 Claims.

My invention relates to projection screens suitable for use with motion-picture apparatus, television apparatus, et cetera, and processes of making the same. The invention is applicable to all screens of this general character or adapted'to be used for similar purposes.

More particularly my invention is an improve ment on the screen and process of producing the same disclosed by United States Letters Patent No. 1,833,317, issued November 24, 1931, to John Crawford. The screen produced according to that patent was a distinct advance in the art in that it gave clear delineation, extraordinary depth and materially reduced eye strain. However, in some theaters of extra width, it has been found that the Crawford screen did not reflect sufficient light to the sides so as to enable spectators on either side of the front of the house to receive as clear and distinct an image as the spectators directly in front of the screen.

Accordingly it is an object of this invention to produce an improved screen by obtaining a'greater diffusion or spread of the reflected light'to the side of the screen, as is obtained to some extent .by the ordinary white screen, while retaining the improved reflecting characteristics of the Crawford screen.

Other objects of the invention will appear from the following description and the appended claims.

The accompanying drawing illustrates preferred embodiments of the invention.

Fig. 1 is a view in perspective of the preferred form of the invention; while Fig. 2 is a plan view of another form.

In Fig. 1 the base of the screen is designated by the reference numeral I. A closely woven fabric may be used for this base. In this case the upper surface of the base is irregularly embossed so as to present numerous depressions 2 and raised portions 3. In the illustration, the depressions 2 are shown coated with a coating composition composed of a metal powder and a material comprising flaky light-reflecting particles, such as is disclosed in the patent to Crawford to which reference is made above. The raised portions 3 are shown without this metallized coating. At close range the resulting screen'has a checkered or mottled appearance, due to this stippling eflect.

A screen with the roughened surface of Fig. 1

may also be produced by using a more openly woven base of coarser thread. In this case the surface of the fabric will be already sumciently roughened and it will not be necessary to emboss the material.

.forms are conceivable which will give improved results over either the Crawford screen or a plain 5 white screen. For example, in Fig. 2 is shown a screen with a base 4. This screen is shown with spaced holes .5 such as are used in screens for projecting sound pictures where the reproducers are located behind the screen. It is, of course, 10 understood that these holes have no bearing on the present invention but are shown in this embodiment to indicate a further example of the applicability of the present invention. Instead of a roughened uppersurface such as is-employed 15 in Fig. 1, the upper surface of the screen base of Fig. 2 is left substantially smooth or flat, but

' the metallized coating used is applied in such a I has been used as a base, the screen must next 30 be embossed. The raised portions need not be regularly spaced noris any specific size essential. The only requirement is that they be small enough so as not to be apparent at the distance from which the projected image is viewed. If, on the 35 other hand, an openly woven base of coarse thread has been used, which presents a roughened surface, the embossing will not, of course, be required. The metallized coating is next 'ap- 4o plied in any conventional manner so that the depressions 2 are covered by the coating and the raised portions 3 are left white. The preferred manner of accomplishing this is to coat the white primed surface with the metallized coating and 45 then wipe or scrape oil the high spots. In this process a small percentage of the metallized coating is left on the white, forming a very thin transparent glaze. It is, of course, understood that the invention is not limited to the order of 50 applying the coating disclosed. For example, instead of running the metallized coating on the white, a similar effect can be obtained by running the white on the metallized coating, or the high spots of the base may be coated with a smooth roller while the white depressions are left exposed.

The screen of Fig. 2 may be produced ,by applying either coating upon the other by means of a stipple roller. The preferred method is to apply the metallized coating by stipple roller upon the white priming coat as a background. It is obvious, however, that a similar effect will be obtained by applying a white coat with a stipple roller upon a surface uniformly coated with the metallized coating. While in either case, an increased diffusion of light to the sides of the screen is obtained, the best results are obtained with the screen having a roughened or embossed surface, as described in connection with Fig. 1.

The proportion of white to metallized area can be varied within rather wide limits to suit the specific needs of any particular installation. For example, in a long, narrow auditorium, where less reflection of light to the side is required, a smaller ratio of white to metallized area would suffice; whereas in a wide and relatively shorter house, a larger ratio would prove desirable. Variations between 25:75 and 75:25 for this ratio have been found to covermost of the situations now encountered in actual practice.

The invention is not intended to be by v the description of specific embodiments above, but

other embodiments coming within the scope pf the appended claims are to be considered within the scope of the invention.

I claim:

1. The'process of coating a projection screen 5 to produce an uneven light-reflecting and distributing surface, comprising the steps of applying a light-colored priming to a sheet of fabric, embossing the sheet, coating the entire surface with a lustrous coating comprising metal powder and flaky light-reflecting particles, and wiping off the raised portions of the embossed sheet while still wet so as to leave the depressed portions coated with the lustrous coating and the raised portions of contrasting appearance beneath a transparent glaze on the wiped surface.

2. A projection screen of the character described comprising a sheet of fabric having an I embossed reflecting surface with alternate raised and depressed areas, a light-colored continuous coating upon said surface, a lustrous coating comprising metal powder and flaky light-reflecting particles superimposed upon said continuous coating in said depressed areas, and a transparent glaze covering said continuous coating in said raised areas.

DAVID EL KNAPP. 

